Strange thing with merging 2 tables

[Anonymous]

Hello community members, 

I have the following situation; 

1 table contains 82K rows

1 table contains 4K rows

In both tables I have a matching column

When I start the merging proces, I see this image below... (80402 of 81819 rows in first table)

When I hit the OK button, I get about 340K of rows...

Is this normal? I would think the max number of rows stays 82K...

Hope someone can provide me with an answer.

Best regards,  

Sander

[Anonymous · Accepted solution]

So,

New303 = 80k rows
New304 = 4k rows

I'm going to assume that Header_referentienummer on both tables contains duplicate values?

So when you merge New304 Values from column "Header_referentienummer" are matching multiple rows on both tables.

Consider the following:
Table A
ID      val1

a	100
a	200

TableB
ID      val2

a	50
a	60

Merged using the ID, gives a Many to many values merge because there are duplicate values in each column, so the end result is the following:
ID       val1   Val2

a	100	50
a	100	60
a	200	50
a	200	60

See how just one duplicate value doubles our data range? If we were to have 3 it'd triple it and so on...